10 files changed, 359 insertions, 0 deletions
diff --git a/mwe/ecs-homemade/CMakeLists.txt b/mwe/ecs-homemade/CMakeLists.txt
new file mode 100644
index 0000000..6267c1a
--- /dev/null
+++ b/mwe/ecs-homemade/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.5)
+project(ecs-homemade)
+
+# Set the C++ standard (optional, but good practice)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+
+# Use the debug mode (otherwise breakpoints are not compiled)
+set(CMAKE_BUILD_TYPE Debug)
+
+add_executable(ecs-homemade
+	src/main.cpp
+	src/ComponentManager.cpp
+	src/Components.cpp
+	src/GameObjectMax.cpp
+)
+target_include_directories(ecs-homemade PRIVATE "${CMAKE_SOURCE_DIR}/inc")
diff --git a/mwe/ecs-homemade/inc/ComponentManager.h b/mwe/ecs-homemade/inc/ComponentManager.h
new file mode 100644
index 0000000..d368516
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include "Components.h"
+#include <cstdint>
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+class ComponentManager {
+public:
+	static ComponentManager & GetInstance(); //Singleton
+
+	ComponentManager(const ComponentManager &) = delete; //Singleton
+	ComponentManager(ComponentManager &&) = delete; //Singleton
+	ComponentManager & operator=(const ComponentManager &) = delete; //Singleton
+	ComponentManager & operator=(ComponentManager &&) = delete; //Singleton
+
+	template <typename T, typename... Args>
+	void AddComponent(std::uint32_t id,
+					  Args &&... args); //Add a component of a specific type
+	template <typename T>
+	void DeleteComponentsById(
+		std::uint32_t id); //Deletes all components of a specific type and id
+	template <typename T>
+	void DeleteComponents(); //Deletes all components of a specific type
+	void DeleteAllComponentsOfId(
+		std::uint32_t id); //Deletes all components of a specific id
+	void DeleteAllComponents(); //Deletes all components
+
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByID(std::uint32_t id)
+		const; //Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByType()
+		const; //Get a vector<> of all components of a specific type
+
+private:
+	static ComponentManager mInstance; //Singleton
+
+	ComponentManager(); //Singleton
+
+	/*
+	 * The std::unordered_map<std::type_index, std::vector<std::vector<std::unique_ptr<Component>>>> below might seem a bit strange, let me explain this structure:
+	 * The std::unordered_map<> has a key and value. The key is a std::type_index and the value is a std::vector. So, a new std::vector will be created for each new std::type_index.
+	 * The first std::vector<> stores another vector<>. This first vector<> is to bind the entity's id to a component.
+	 * The second std::vector<> stores unique_ptrs. Each component can be gathered via an unique_ptr. This second vector<> allows multiple components of the same std::type_index for one entity (id).
+	 */
+	std::unordered_map<std::type_index,
+					   std::vector<std::vector<std::unique_ptr<Component>>>>
+		mComponents;
+};
+
+#include "ComponentManager.hpp"
diff --git a/mwe/ecs-homemade/inc/ComponentManager.hpp b/mwe/ecs-homemade/inc/ComponentManager.hpp
new file mode 100644
index 0000000..d6da8e8
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.hpp
@@ -0,0 +1,127 @@
+
+template <typename T, typename... Args>
+void ComponentManager::AddComponent(std::uint32_t id, Args &&... args) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		== mComponents
+			   .end()) { //Check if this component type is already in the unordered_map<>
+		mComponents[type] = std::vector<std::vector<std::unique_ptr<
+			Component>>>(); //If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+	}
+
+	if (id
+		>= mComponents[type]
+			   .size()) { //Resize the vector<> if the id is greater than the current size
+		mComponents[type].resize(
+			id
+			+ 1); //Initialize new slots to nullptr (resize does automatically init to nullptr)
+	}
+
+	mComponents[type][id].push_back(std::make_unique<T>(std::forward<Args>(
+		args)...)); //Create a new component of type T using perfect forwarding and store its unique_ptr in the vector<>
+}
+
+template <typename T>
+void ComponentManager::DeleteComponentsById(std::uint32_t id) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		std::vector<std::vector<std::unique_ptr<Component>>> & componentArray
+			= mComponents[type]; //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			componentArray[id]
+				.clear(); //Clear the whole vector<> of this specific type and id
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::DeleteComponents() {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		mComponents[type]
+			.clear(); //Clear the whole vector<> of this specific type
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByID(std::uint32_t id) const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 componentArray[id]) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.push_back(
+						*castedComponent); //Add the dereferenced raw pointer to the vector<>
+				}
+			}
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByType() const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+	//std::uint32_t id = 0;	//Set the id to 0 (the id will also be stored in the returned vector<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		for (const std::vector<std::unique_ptr<Component>> & component :
+			 componentArray) { //Loop through the whole vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 component) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.emplace_back(std::ref(
+						*castedComponent)); //Pair the dereferenced raw pointer and the id and add it to the vector<>
+				}
+			}
+
+			//++id;	//Increase the id (the id will also be stored in the returned vector<>)
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
diff --git a/mwe/ecs-homemade/inc/Components.h b/mwe/ecs-homemade/inc/Components.h
new file mode 100644
index 0000000..98c5fe7
--- /dev/null
+++ b/mwe/ecs-homemade/inc/Components.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <string>
+
+class Component {
+public:
+	Component();
+
+	bool mActive;
+};
+
+class Sprite : public Component {
+public:
+	Sprite(std::string path);
+
+	std::string mPath;
+};
+
+class Rigidbody : public Component {
+public:
+	Rigidbody(int mass, int gravityScale, int bodyType);
+
+	int mMass;
+	int mGravityScale;
+	int mBodyType;
+};
+
+class Colider : public Component {
+public:
+	Colider(int size);
+
+	int mSize;
+};
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.h b/mwe/ecs-homemade/inc/GameObjectMax.h
new file mode 100644
index 0000000..3029053
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+class GameObject {
+public:
+	GameObject(std::uint32_t id, std::string name, std::string tag, int layer);
+
+	template <typename T, typename... Args>
+	void AddComponent(Args &&... args);
+
+	std::uint32_t mId;
+	std::string mName;
+	std::string mTag;
+	bool mActive;
+	int mLayer;
+};
+
+#include "GameObjectMax.hpp"
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.hpp b/mwe/ecs-homemade/inc/GameObjectMax.hpp
new file mode 100644
index 0000000..91d51ea
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.hpp
@@ -0,0 +1,7 @@
+#include "ComponentManager.h"
+
+template <typename T, typename... Args>
+void GameObject::AddComponent(Args &&... args) {
+	ComponentManager::GetInstance().AddComponent<T>(
+		mId, std::forward<Args>(args)...);
+}
diff --git a/mwe/ecs-homemade/src/ComponentManager.cpp b/mwe/ecs-homemade/src/ComponentManager.cpp
new file mode 100644
index 0000000..536c152
--- /dev/null
+++ b/mwe/ecs-homemade/src/ComponentManager.cpp
@@ -0,0 +1,23 @@
+#include "ComponentManager.h"
+
+ComponentManager ComponentManager::mInstance;
+
+ComponentManager & ComponentManager::GetInstance() { return mInstance; }
+
+ComponentManager::ComponentManager() {}
+
+void ComponentManager::DeleteAllComponentsOfId(std::uint32_t id) {
+	for (auto & [type, componentArray] :
+		 mComponents) { //Loop through all the types (in the unordered_map<>)
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			componentArray[id]
+				.clear(); //Clear the components at this specific id
+		}
+	}
+}
+
+void ComponentManager::DeleteAllComponents() {
+	mComponents.clear(); //Clear the whole unordered_map<>
+}
diff --git a/mwe/ecs-homemade/src/Components.cpp b/mwe/ecs-homemade/src/Components.cpp
new file mode 100644
index 0000000..c8347b3
--- /dev/null
+++ b/mwe/ecs-homemade/src/Components.cpp
@@ -0,0 +1,11 @@
+#include "Components.h"
+#include <iostream>
+
+Component::Component() : mActive(true) {}
+
+Sprite::Sprite(std::string path) : mPath(path) {}
+
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType)
+	: mMass(mass), mGravityScale(gravityScale), mBodyType(bodyType) {}
+
+Colider::Colider(int size) : mSize(size) {}
diff --git a/mwe/ecs-homemade/src/GameObjectMax.cpp b/mwe/ecs-homemade/src/GameObjectMax.cpp
new file mode 100644
index 0000000..b0c5af7
--- /dev/null
+++ b/mwe/ecs-homemade/src/GameObjectMax.cpp
@@ -0,0 +1,7 @@
+#include "GameObjectMax.h"
+
+#include "ComponentManager.h"
+
+GameObject::GameObject(std::uint32_t id, std::string name, std::string tag,
+					   int layer)
+	: mId(id), mName(name), mTag(tag), mActive(true), mLayer(layer) {}
diff --git a/mwe/ecs-homemade/src/main.cpp b/mwe/ecs-homemade/src/main.cpp
new file mode 100644
index 0000000..330e154
--- /dev/null
+++ b/mwe/ecs-homemade/src/main.cpp
@@ -0,0 +1,59 @@
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <vector>
+
+#include "ComponentManager.h"
+#include "Components.h"
+#include "GameObjectMax.h"
+
+int main() {
+	auto startAdding = std::chrono::high_resolution_clock::now();
+
+	GameObject * gameObject[100000];
+
+	for (int i = 0; i < 100000; ++i) {
+		gameObject[i] = new GameObject(i, "Name", "Tag", 0);
+
+		gameObject[i]->AddComponent<Sprite>("C:/Test");
+		gameObject[i]->AddComponent<Rigidbody>(0, 0, i);
+		gameObject[i]->AddComponent<Colider>(i);
+	}
+
+	auto stopAdding = std::chrono::high_resolution_clock::now();
+
+	//This is what systems would do:
+
+	std::vector<std::reference_wrapper<Sprite>> sprites
+		= ComponentManager::GetInstance().GetComponentsByType<Sprite>();
+	for (Sprite & sprite : sprites) {
+		//std::cout << sprite.get().mPath << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Rigidbody>> rigidBodies
+		= ComponentManager::GetInstance().GetComponentsByType<Rigidbody>();
+	for (Rigidbody & rigidbody : rigidBodies) {
+		//std::cout << rigidbody.get().mMass << " " << rigidbody.get().mGravityScale << " " << rigidbody.get().mBodyType << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Colider>> coliders
+		= ComponentManager::GetInstance().GetComponentsByType<Colider>();
+	for (Colider & colider : coliders) {
+		//std::cout << colider.get().mSize << std::endl;
+	}
+
+	auto stopLooping = std::chrono::high_resolution_clock::now();
+
+	for (int i = 0; i < 100000; ++i) {
+		delete gameObject[i];
+	}
+
+	auto Addtime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopAdding - startAdding);
+	auto LoopTime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopLooping - stopAdding);
+	std::cout << "AddTime: " << Addtime.count() << " us" << std::endl;
+	std::cout << "LoopTime: " << LoopTime.count() << " us" << std::endl;
+}